This invention is concerned with an improvement in a burner sometimes called a double vortex burner of the types generally shown in U.S. Pat. Nos. 2,736,168; 3,200,870 and 3,352,345. The double vortex burners disclosed in the aforesaid patents were believed to provide a flow of combustibles whereby the particulate matter would be entrained for a sufficient period to permit substantially complete combustion thereby rendering such burners suitable for the combustion of solid matter which was otherwise considered difficult to burn.
However, the burners of the prior art did not live up to their expectations and it was found in some instances that unburned particulate was delivered with the exiting gases and that, in some cases, the particulate collected on the walls of the burner thereby reducing complete combustion and requiring shut-down for cleaning of the burner.